Salmonella spp

Salmonella spp are a group of significant, highly prevalent, Gram-negative, rod-shaped bacteria of the family Enterobacteriaceae. This bacteria are facultative intracellular pathogens which has many different serotypes, which can be divided into two main groups—typhoidal and nontyphoidal. It is only the nontyphoidal serotype which are zoonotic---meaning they can be transferred from humans to animals and from animals to humans. This bacteria is found naturally is the gastrointestinal tract of carrier animals and humans, especially reptiles. Collectively, infection with any Salmonella species causes Salmonellosis.

Many birds infected with Salmonella are asymptomatic (meaning they do not have any clinical signs of illness). Others may develop an acute, rapidly fatal septicemia, or chronic localized infection.

Younger birds are more susceptible then adults, largely due to the immaturity of their intestinal flora. Chicks from mail-order hatcheries are frequent carriers of Salmonella spp. In fact, the proportion of mail-order hatchling boxes which tested positive for Salmonella was higher in 2015 (27%) compared to 2014 (17%).

The reason why older birds are less commonly infected with Salmonella spp is because they have developed a normal intestinal flora from their environment, which protects them against invasion with this bacteria, either by competing for intestinal carrier sites or by producing antagonistic factors that inhibit their growth.

Salmonella survival in the environmentSalmonella are able to remain infectious in the environment for several weeks. Salmonella bacteria are not destroyed by freezing. Heat and exposure to UV light can help accelerate their destruction.

How Salmonella is transferred
Most birds become infected through exposure to feces from birds carrying this bacteria. It is also found commonly in environments such as slaughter houses (abattoirs), septic tanks, sewage effulents, etc.